that sounds surprisingly light. when i set up my anchoring i used 6mm chain and was told that 14mm warp would be ideal but i had to go down to 12mm because that was the size required for the windlass.
I know, it does....but they are the minimum requirements for coded vessels, so a good minimum for light boats in sheltered use possibly.
I went for larger personally.
Do make sure that you will be physically able to get the pairs through, if you are going to splice this yourself. I inherited a great deal of 24mm octoplait and wanted to splice it onto my 10mm chain but it is just a bit too big - can't get it through. So I will have to go out and buy a length of 16mm or 18mm just to be able to physically splice it.